Lead through insulator



Oct. 17, 1961 R. ABRAMS LEAD THROUGH INSULATOR Original Filed Feb. llI 1957 LEAD 'rrnioUGny INsULAToR Ralph Abrams, Sharon, Mass., assigner to Cambridgev Thermionic Corporation, Cambridge, Mass., a corporation of Massachusetts Original application Feb. 11, 1957, Ser. No. 639,325, now Patent No. 2,931,008, dated Mar. 29,1960. rDivided and this application Dec. 21, 1959, Ser. No. 1,835

3 Claims. (Cl. 174-152) yThis invention relates to composite insulators for use in electrical installations, generally speaking of the lead through and connector types which can bef mounted in apertures of supports such as panels or chassis and which are capable of receiving therewithin conducting means such as soldering lugs or jacks.y This application is a division of my application Serial No. 639,325, filed February 11, 1957, now Patent No. 2,931,008 of March 29,` 1960.

The principal object of the invention isto provide devices of the above character which are especially suited for the incorporation therein of superior electrically in-y sulating materials of the types exemplified by polyflnoroethylene polymers which have little elastic tendency or memory to return to an original shape after having been more or less suddenly deformed, or at least a tendency to become permanently deformed under continuous stress, but which on the other hand have a comparatively high tendency to gradual flow due to low internal molecular friction. Such materials are ill suited for incorporation in conventionally designed and fabricated devices of the above type and it was found to be quite important to find techniques for providing, in a commercially acceptable way, assemblies which permit the safe use of such insulating materials, taking advantage of the above-mentioned electrical characteristics thereof.

` Other objects are to provideV improved vinsulating as-` devices which can be easily assembled or mounted on panels of widely varying typesand to provide insulated assemblies of this type which lendthemselves especially well to miniaturizing. Y

n A brief summary indicating the nature and substance of the invention, for attaining the above objects, characterizes its principal aspects as follows. Composite articles `such as insulating mounts to which the invention is applied comprise an essentially cylindrical insulator body of material having the above-mentioned properties characteristic of polyliu-oroethylenessuch as appreciable tendency to flow due to low internal friction and little tendencyto return elasticallyto an original shape, this insulator body having an axial cavity and two transverse deformation faces one being preferably at an end of the insulator body and the other extending at an intermediate region; a metal insert with connecting means and a core that fits the cavity of the insulator body and has a polygonal such as knurled or hexagonal portion; a metal mounting shell fitting around the insulator body; and on the pin and the shell insulator confining faces which contact, upon assembly, respective ones of the deformation faces of the insulator body such `that the insulator material is forced to fill the space between pin and shell and to bulge outwardly into the open space be- ICC 2 tween the now contacting, confining and deformation faces. In this manner the insulator is on the one hand sutiiciently deformedy for permanently firm 'attachment by confinement between the*y faces, the pin core and the shell and on the other hand sufiicientlyrestrained to prevent any flowing from such confinement. The polygonal portion of the insert pin becomes firmly lodged between the faces and prevents rotational displacement. n

In an importantk practical embodiment, the deformation faces are constituted by the two outer transverse surfaces of an axially recessed cylindrical head of the insulator body, and the confining faces are constituted by the inner transverse face ofan axial end recess of the shell and by a transverse face of a collar of the insert pin which also has a polygonal collar portion embedded between the y faces to prevent rotational as well as axial displacement of the three components, with the aid of the'bulge of the insulating body. n

These and other objects and aspects of. the invention will appear from the Vfollowing description of two typical embodiments thereof illustrating its novel characteristics. This description refers to a drawing in which v FIG. 1 is atop View of a feed through insulator according to the invention;

FIG. 2 is a side elevation partly in section on lines 2-2 of FIG. l, of the fully assembled feed through insulator; and

FIG. 3 is a section on lines `2 2 of FIG. l of the components of the insulator during assembly prior to the final securing and with the parts in preformed shape as yet not deformed by the assembling operation.

FIG. 3 shows the components of an assembly according to FIGS. l and 2 in their preformed shape prior to final joining. These components consist of a metal insert pin 11, an insulator body 21, and a shell 31.

The insert -pin y11 constitutes the conducting core 14 of the assembly and has an hexagonal collar 12 'as well as a confining collar 16 with a confining face 16.1. .On one or both sides the core extends into lugs with flanges 11.1 or an annular recess 11.2,' for soldering conductors thereto. It will be understood that other conductor connecting provisions can be used instead of the soldering lugs.

The insulator body is indicated at 21 and comprises prior to assembly a cylindrical body portion 22 which is preformed to fit the core portion 14 ofthe insert 11, and a head portion 23 which has a cylindrical recess 24 which accommodates thehexagonal collar 12 of the insert. The deformation faces of the insulator body are indicated at 26.1 and 26.2. The insulator body 21 is made of synthetic material of the peculiar type for which, as mentioned above, the herein described construction is espe-V cially suited.` This material comprises certain compounds,

, of the polyethylene and especially of the polyfluoroethyl-v ene type which have particularly favorable electrical and mechanical properties, such as polyethylene, polychlorotrifluoroethylene and polytetrafluoroethylene resins commercially available under the trade names Alathon, Kel-F and Teflon respectively. These materials exhibit peculiar .y i

properties which make them unsuitable for conventional `assembly with metal components. They arenon-adhesive, inelastic in the sense that they have a poor memory of previous shape and that they are of comparatively low f viscosity in the sense that they have little internal friction so that they are easily deformable and have a tendency to flow around obstructing surfaces. The present invention 3 and, annually extending therefrom a staking rim 35. The confining face of the head 33 is indicated at 36.1.

For assembling this feed through insulator, the three components are inserted into eachother las indicated in FIG. 3. Thereupon the rim 35 is pressurably forced inwardly towards and somewhat into the head portion-23 of the insulator body 21, with the result indicated in FIG. 2, namely with the insulating material being forced into the space between the confining faces 16.1 and 36.1 of the insert and the shell, respectively. Thus, the insulating material of the above described character is deformed to assume the shape of the spacebetween these conning faces 16.1 and 36.1 which after assembly contact the deformation faces 26.1 and 26.2 of the insulator body which is forced to bulge outwardly at 26 (FIG. 2) into the opening between the confining faces of insert and shell. During the deformation of the insulator body it is also forced to flowY around the hexagonal collar 16 which becomes thus embedded in the insulating material between the now contacting confining-.and deformationfaces, as clearly shown in FIG. 2. The polygonal collar prevents rotatory aswell as axial loosening of the assembly. After assembly, the inner surface of the curved-in lip of the rim 35 Vand the contacting insulator surface also constitute confining and deformation faces, respectively. In this manner the insulating material is sufficiently deformedto become permanently and firmly attached to the two metal parts 11 and 31 by confinement between the face 16.1 of the insert pin and the face 36.1 of the shell, but-it is also sufficiently prevented from flowing from such confinement. l

This assembly can be mounted in any convenient manner, for example by inserting it into a hole of a panel pA such as indicated in FIG. 2 and by fastening-it therethrough with a nut or other fastening means. Conductors canbev joined to one or both lugs by soldering -or any other means serving the purpose at hand; the solder-lug collars or recesses 11.1, 11.2 can be omitted or replaced by appropriate joining means. Y

While it is .difficult to form a fuily satisfactory theoretical explanation of the behavior of the abovecharacterized polymers in assemblies or" this type, it appears that according to the invention, the fiowing properties can be taken advantage of for momentarily deformingthe insulator during. assembly while the lack of elasticity prevents subsequent long range deformation, with the bulging portions of the polymer body probably promoting this behavior; at any rate it has been confirmed Vby `ample practical experience that composite articles which are preformed Vand assembled in this manner described with reference to the above two examples retain their shape and effectiveness through any use for which such permanency can be reasonably expected.

It should be understood that the present disclosure is for thepurpose of illustration only and that this invention includes all modifications and equivalents which fall Within the scope of the appended claims.

I claim: Y

l. A composite article such as an insulating mount, comprising: an insulator body of material having physical properties characteristic of polyfiuoroethylenes such as appreciable tendency to flow due to low internal friction` and little tendency elastically to return after deformation to an original shape, said insulator body having ya cylindrical cavity and two transversewdeformation faces, one at kanend of the insulator body and the other extending outwardly at an intermediate region thereof, forming an outwardly extending head portion between said deformation faces; a metal insert having connecting means at an end thereof, a core portion that fits said cavity of the insulator body, a transverse insulator confining face between said core portion and said connecting means and contacting said deformation face at an end ofthe insulator body, and a collar portion at the region of said head portion between said transverse confining faces of the insulator body; and a metal shell having a sleeve fitting around said insulator body and extending from said intermediate deformation face of the insulator body with an edge around said head portion beyond said collar portion of the metal insert, and said shell having inwardly extending transverse confining means contacting said outwardly extending intermediate deformation face of the insulator body, said head portionbeing confined in said shell under pressure to provide contact of said deformation faces of the insulator body withsaid confining face and said collar portion of the insert, the insulator body filling the space between the insert and the shell forming a bulge extendingk outwardly into the open space between said transverse confining face ofthe insert and said edge; whereby the insulator body is on the one hand sufficiently deformed to provide permanently firm attachment tothe insert and the shell-by confinement between the confining face and the core of the insert, the sleeve and the confining meansV of the shell, and is-on the otherhand sufficiently restrained to prevent liowing from such confinement.

2. Article according to claim 1 wherein said collar portion of the metal insert is non-circular to prevent rotational as well as axial displacement between said insulator body, said metal insert and said metal shell with the aid of said bulge.

3.fA composite article such as an insulating mount, comprising: an insulator body of material having physical properties characteristic of polyfiuoroethylenes such as appreciable tendency to fiow ydue to low internal friction and little tendency elastically to return after deformation to an original shape, said insulator body having an axial bore therethrough andl two transverse deformation faces, one at an end of the insulator body and the other extending outwardly atV an intermediate exterior region thereof, forming an outwardly extending -head portion between said deformationfaces; a metal insert extending through said bore and having connecting means, a transverse insulator confining face, and a core that fits said bore at said head portion; and a metal mounting shell fitting around saidinsulator body and having an inwardly extending transverse insulator confining face, said confining faces pressurably .contacting .respective ones of said deformation faces of said insulator body, and said shell extending into the region between said deformation faces and vsaid confining faceswith said insulatingtmaterial filling the space between the insert and the shell and bulging outwardly into the open space'between the conlining faces; whereby the insulator body is on the one hand sufficiently deformed to provide permanently firm attachment to the insert and the shell by confinement between said faces and the insert core and the shell, and is on the other hand sufficiently restrained to prevent owing from such confinement.

Flanagan Ian. 18, 1955 Demurjian Dec. 6, 1955 

